The present invention generally relates to a system for dispensing fluids. More specifically, the present invention relates to a one-way valve assembly for dispensing fluid from a collapsible container. The valve assembly of the present invention also prevents backflow into the container prior to, during and following distribution of the fluid, thereby keeping unwanted items such as contaminants out of the container.
There is a great need in many industries to dispense fluid products that are susceptible to oxidation and contamination safely. Many products lose their freshness, potency and/or sterility after only a brief period of use. This period or xe2x80x9cuse lifexe2x80x9d varies from product to product. Generally, when fluids are dispensed from a valve assembly, the volume of product delivered from the valve assembly is replaced with an equivalent volume of air. Exposure to this ambient air leads to the entry of oxygen into the container and potentially to contaminants in the air such as microorganisms, atmospheric gases, moisture and dust particles. The quality, potency, safety and/or sterility of the remaining product can be compromised by the air and potential contaminants within.
The present invention delivers fluid under positive pressure through a one-way valve from a container that collapses in proportion to the amount of product dispensed. Consequently, air does not enter the dispensing system.
The concept of a one-way valve assembly is not new. One-way valves are used extensively throughout the medical field in complex medical device machinery to dispense flowable products. One-way valves are also being used in aerosol dispensers to dispense flowable products. However, the need for a contamination-safe, propellant-free one-way valve that can easily be manufactured and assembled has long been apparent. As the medical field continues to grow, the need to dispense multiple doses of sterile fluids during surgery, diagnostic testing, ophthalmology and other areas without fear of contamination continues to grow as well. Thus, there exists a need for creating a collapsible dispensing system that is simple to manufacture and assemble for dispensing multiple doses of sterile fluids.
Several one-way valves contain cylindrical cores encompassed by an elastic cylindrical sheath. The core typically has an entrance tube leading to one area of the sheath, and an exit tube leading away from another area of the sheath. The entrance and exit tubes, while enclosed by the sheath, do not interconnect. To dispense liquid, one would apply pressure to expand the sheath, allowing liquid to pass from the entrance tube to the exit tube. Upon release of that pressure, the sheath would contract, thereby sealing the valve and preventing backflow into the container.
For example, U.S. Pat. Nos. RE 34,243; 5,836,484; 5,279,330; 5,305,783; 5,305,786; 5,080,138; 5,080,139; and 5,092,855 all disclose cylindrical one way valves for dispensing liquids and eliminating backflow of unwanted materials. Some of these, such as U.S. Pat. No. 5,080,138, have an excessive number of parts. All of these, particularly the disc shaped valves in U.S. Pat. Nos. 5,080,139 and 5,279,330, are unnecessarily difficult to assemble.
Referring to FIG. 1, shown is a dispensing valve assembly for dispensing liquids of different consistencies according to U.S. Pat. No. RE 34,243. Shown is valve assembly 11 containing five pieces. Valve assembly 11 is mounted on flexible container 13 such that fluid will be dispensed when container 13 is compressed. Valve assembly 11 is constructed by stretching sheath 15 over the outside of valve body (not pictured). Sheath 15 is sealed on the outside surface of the valve body by O-rings 17.
The five-piece design disclosed in U.S. Pat. No. RE 34,243, and shown in FIG. 1, has several disadvantages. First, the five-piece design makes the unit costly to manufacture, as at least four distinct units must be manufactured, and each unit must be constructed with precision. The existence of such a five-piece apparatus also necessarily indicates a level of complexity when assembling. Sheath 15 must be stretched over valve body (not pictured) and then secured in place over O-rings 17. This process is difficult to accomplish.
Referring now to FIG. 2, shown is the valve assembly of U.S. Pat. No. 5,305,783. Shown is valve body 21 covered by elastomeric sleeve 23 with O-ring like enlargements 25 at the each end. Elastomeric sleeve 23 is secured to valve body 21 by O-ring like enlargements 25 by forming a seal at reduced diameter ends 27 of valve body 21. This design renders assembly of such a valve difficult.
To illustrate, the steps required to attach elastomeric sleeve 23 onto valve body 21 are shown in FIGS. 3A-3D. Elastomeric sleeve 23 is first formed on molding core pin 29 as shown in FIG. 3A. Elastomeric sleeve 23 must then be rolled up on itself on molding core pin 29 as depicted in FIG. 3B. Molding core pin 29 is then removed as depicted in FIG. 3C. Elastomeric sleeve 23 is then placed on valve body 21 with O-ring like enlargement 25a and elastomeric sleeve 23 is secured to reduced diameter end section 27 of valve body 21 as shown in FIG. 3D. The assembly is completed when elastomeric sleeve 23 is unrolled and O-ring like enlargement 25b secures the reduced diameter end section 27 of the valve body 21 as resulting in the configuration shown in FIG. 2.
This process could be done manually but it would be time consuming. Alternatively, the assembly process could be automated but would involve an unacceptable rate of failure resulting in increased expense.
Referring now to FIG. 4, shown is a valve assembly according to U.S. Pat. No. 5,092,855. Sheath 31 has O-rings 33 at both ends of valve body 35. O-rings 33 secure sheath 31 to valve body 35 when O-rings 33 seat into annular grooves formed on the outside of valve body 35. Sheath 31 is further secured by enclosing sleeve 37 which fits over sheath 31 and valve body 35 and ensures sheath 31 and valve body 35 are sealed. Once again, sheath 31 must be stretched over valve body 35 rendering assembly of such a valve difficult and costly to manufacture on a commercial scale.
Referring next to FIG. 5, shown is a valve assembly according to U.S. Pat. No. 5,305,786. As shown, valve body 41, elastomeric member 43 and cover member 45 are cylindrical. This cylindrical design is a disadvantage during assembly. For the valve assembly to operate as described, the diameter of cylindrical section 47 of valve body 41 must be only slightly smaller than the diameter of cylindrical section 49 of cover member 45. Therefore, insertion of valve body 41 into elastomeric member 43 and subsequently into cover member 45 can tolerate only slight deviations in any direction perpendicular to the axis of the valve.
Referring again to FIG. 1, to assemble a valve assembly such as the one depicted, sheath 15 is typically rolled axially onto a mandrel or support pin and then carefully rolled up from one end toward the other in preparation for placement on valve body (not pictured). Alternatively, sheath 15 can be fitted on arms for lateral expansion with compressed air while the valve body is inserted into sheath 15. In either case, assembly, whether performed manually or by complex machinery, is slow, cumbersome, and sometimes ineffective. Another disadvantage with the design depicted in FIG. 1 is that sheath valve is cylindrical, thereby requiring the inside diameter of the sheath to be marginally smaller than the outside diameter of the valve body in order to maintain the necessary sealing tension of sheath 15 against the valve body. As stated above, the cylindrical design necessarily makes the valve assembly of FIG. 1 difficult and costly to manufacture and assemble.
Referring now to FIG. 6, shown is a multiple dose dispensing system according to U.S. Pat. No. 5,836,484. Shown are dispensing cartridge 51, container 53, delivery block 59 and sheath 55 all contained within housing 57. Delivery block 59 dispenses liquid 61 through sheath 55, and sheath 55 prevents the backflow of contaminants into delivery block 59.
The valve assembly system depicted in FIG. 6 also has several disadvantages. One disadvantage is that for the design to function properly, sheath 55 must stretch over or envelop delivery block 59. While O-rings are not part of this invention, the stretching of sheath 55 onto delivery block 59 is a complicated process which slows manufacturing. Another disadvantage is the necessity of protrusions 63 to keep sheath 55 from shifting, contracting, or falling off of delivery block 59. Further, as before, to ensure that sheath 55 fits tightly on delivery block 59, the diameter of sheath 55 as manufactured must be smaller than the outer diameter of delivery block 59. While this design necessarily ensures a taut fit, it causes grave problems during assembly, when a flexible material must tightly envelop a block with a smaller diameter. Therefore, the complications and costs associated with manufacturing such a design and assembling such a valve can be overbearing in a mass product market.
The present invention discloses a valve assembly for dispensing flowable materials, wherein said valve assembly comprises a valve body having a longitudinal bore therethrough, an elastomeric sheath having a longitudinal bore therethrough and an enclosing sleeve having a longitudinal bore therethrough, wherein all of said valve body, said elastomeric sheath and said enclosing sleeve are conically shaped, and wherein all of said longitudinal bores of said valve body, said elastomeric sheath and said enclosing sleeve are coaxial.
An object of the present invention is to provide a one-way valve which is easily manufactured. The present invention provides a three-piece system which can be manufactured at a lower cost. The system eliminates the use of O-rings and other methods of keeping the sheath attached to the valve body, and dispenses with other non-essential parts.
Another object of the present invention is to provide a one-way valve which is easily assembled. The present invention has a conical valve body and a conical elastomeric sheath. The conical shape of these two pieces facilitates the lateral enclosure on the outside surface of the valve body, thereby allowing simple assembly of the unit. The present invention also comprises a rigid sleeve laterally enclosing the elastomeric sheath, spaced radially outward from the elastomeric sheath. This design limits the radially outward displacement of the elastomeric sheath thus preventing sheath membrane distortion or ballooning. Therefore the conical valve assembly can be easily manufactured and assembled on a small scale as well as in a mass market.
Yet another object of the present invention is to provide a means for venting the space between the sleeve and the sheath in a one-way valve assembly. By venting the space, air pressure will not build up, and the sheath can expand without unnecessary force and rebound easily into sealing contact with the valve body upon release of pressure.
Other objects, features, and characteristics of the present invention, as well as the methods of operation and functions of the related elements of the structure, and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following detailed description with reference to the accompanying drawings, all of which form a part of this specification.